The invention relates to a splicing arrangement for the connecting of yarns, particularly staple fiber yarns. Such splicing arrangement has a splicing head comprising a longitudinal groove for receiving the yarns to be spliced, yarn clamps, cutting devices, loop pulling devices and devices for preparing the yarn ends cut with respect to the length which are arranged on both sides of the longitudinal groove and each contain a friction surface moving toward the end of the yarn ends introduced into it.
In order to obtain a spliced connection which has high strength and differs as little as possible from the remaining yarn, it is, as a rule, necessary to prepare the yarn ends. In this case, the spinning twist is removed from the fiber ends, and the fiber ends are thinned out. In practice, it is generally customary to use devices for the preparing of yarn ends in which the preparing takes place by an effect of air currents, particularly compressed-air jets (see Swiss Patent Document CH-A 658445). Although devices of this type technically are relatively easy to implement, the difficulty exists of apportioning the preparation such that, on the one hand, the yarn ends are prepared sufficiently but, on the other hand, are not thinned out excessively and, under certain circumstances, are also not shortened too much. In this case, the intensity of the preparation is set by the duration of the influence of the air jets on the fiber ends.
Although it has become known to combine the preparation by means of compressed-air jets with an additional preparation by means of the effect of a friction surface (German Patent Document DE-A 31 51 270), as far as is known, devices of this type have not been used in practice. In this known construction, the yarn ends are applied by means of the compressed-air jets to a turbine rotor which is acted upon on the outside and is driven by means of the compressed-air jets. This turbine rotor, onto the circumference of which the yarn end is blown, has the purpose of causing a rubbing, pulling and tearing treatment of the fiber ends. By means of this relatively expensive device, it is, however, also not possible to cause a preparation of the yarn ends to precisely the desired extent of the opening-up.
It is an object of the invention to provide a splicing arrangement of the initially mentioned type with a device for preparing the yarn ends in which the preparing can be adjusted very precisely and is carried out in a controlled manner.
This object is achieved according to the invention by providing an arrangement wherein a driven apron is used in each case as the friction surface and, with a countersurface, forms a gap receiving the yarn end to be prepared. In this manner, a purely mechanical preparation of the yarn ends is carried out that can be precisely controlled. In this case, it is another advantage that this preparing is not dependent on the direction of the twist that was previously contained in the yarn. The purely mechanical effects can in this case be precisely controlled, not only with respect to their duration but also with respect to their intensity and length.
In an advantageous development of preferred embodiments of the invention, it is provided that the gap tapers in a wedge shape away from the inlet side. This results in the special advantage that the mechanical effect on the yarn ends increases in the direction of the actual end so that a particularly advantageous thinning-out of the yarn can be implemented in a controlled manner. In an advantageous development, it is also provided that the apron is guided on the inlet side, around a deflecting element, the distance of which can be adjusted with respect to the countersurface. As a result, the tapering of the wedge-shaped gap can be adjusted and can be adapted to the yarn to be spliced. In particular, an adaptation to the staple lengths of the fibers of the yarn to be spliced is also possible in this manner.
In a further development of the invention, it is provided that a second apron, which moves in the same direction as the first apron, is provided as the countersurface. In this manner, it is achieved that the yarn ends are worked from two sides, so that a very uniform preparation is achieved.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.